This invention relates to a device for transferring heat energy to heat or cool a surface.
It is known to transfer heat energy over a distance. For example, in U.S. Pat. No. 2,350,348 a rod-like heat conducting device is described. The arrangement disclosed therein is based on the principle that heat may be transferred in a closed system which is partially filled with a vaporizable liquid. At one location of the device, heat is absorbed by vaporizing the liquid and at another location, remote from the first location, such heat is released by condensation. The vaporization of the liquid, that is, the absorption of heat takes place conventionally at a location which is situated below the height level of the location where the condensation (that is, the heat release) is taking place. In order to change this natural circulation, the above-noted United States patent proposes the use of a heat transfer element which is a closed tube having an internal capillary structure formed, for example, of sintered iron powder which, dependent upon the liquid to be used or the height to which the heat has to be transferred, may be mixed with other substances. For example, in a refrigerator, by virtue of such an arrangement heat may be transferred downwardly from above, and cold may be transferred upwardly from below.
A similar arrangement is disclosed in U.S. Pat. No. 3,152,774. In manmade satellites, a cooling system must be provided for that face of the solar panels which are turned towards the sun. The solar panels, in order to reduce their weight, should contain only as much metal as necessary for ensuring stability of the structure. Water, methyl chloride or a Freon may be used as the heat transfer medium. The heat transfer medium is advanced from a central reservoir by means of a fiber-like material which lines the pipe system and the reservoir and which acts as a wick to advance the liquid to the location of use, that is, the location where a vaporization takes place. Such an arrangement is expedient primarily because the system is in a weightless state and consequently it is not necessary to overcome the weight of the liquid during its transfer.
Similar problems are involved in the field of machinery. Either heat should be transferred from a heating element to a heating surface, such as in heat sealing shoes in packing machines which work on heat-sealable wrapper material or heat should be removed from a working location such as high precision machine tools or the like. Problems involved in such an application are addressed in U.S. Pat. No. 4,288,968 which discloses a system wherein the sealing face of a heat sealing shoe is heated by means of a condensating gas. The gas is confined to a cavity or a closed pipe system between the heat elements and the sealing face. At all times a sump of condensated liquid is present which gathers at the lowest location due to gravity. Consequently, the heating mechanism should be arranged at such lowest location. The sealing shoes, however, are in most cases rotary structures so that the sump, because of centrifugal forces, is at a different location.